The present invention relates generally to floor cleaning appliances driven by an electric motor, and more particularly it relates to a method of and a device for the indication of the optimum adjustment of the length of bristles of a brush or bristle roller projecting from the housing of the floor cleaning appliance, particularly of a carpet cleaner.
In conventional floor cleaning appliances having a bristle roller driven by an electric motor, such as in the case of electrically operated carpet brushes, it is not possible to adjust the length of bristles projecting from the housing so as to meet exactly the requirements for the optimum operation of the appliance. The adjustable length of the bristles projecting from the housing determines the degree of engagment of the brush or bristle roller with the floor or carpet to be cleaned. An exact adjustment of the right length of the projection of the bristle roller from the housing is, therefore, particularly important inasmuch as in the case of insufficient length the cleaning effect considerably decreases or almost disappears and in the case of an excessive length of the projecting bristles the torque in the driving electromotor unduly increases so that the motor together with its transmission element (such as a transmission belt) are excessively loaded. In addition, if the brush roller is adjusted to a position where its bristles project too far from the appliance housing, there is the danger that the fabric of the carpet being cleaned may become damaged.